Paper machinery



March 18, 1952 A, STA GE 2,589,639

PAPER MACHINERY Filed 001;. 1'7. 1947 r 2 SHEETSSHEET 1 IN VEN TOR.

W BY ATTORNEYS Filed Oct. 17, 1947 5. A. STAEGE PAPER MACHINERY soj 88 OO 77 8/ 85 62 :CL

a T I: INVENTOR.

Mia/J ATTORNEYS Patented Mar. 18, 1952 Stephen :A. *Staege, Hamilton,Ohio, 'assignor to TheBlack-Clawson Company, Hamilton, Ohio,

. a corporation of Ohio SApplica t-ion c'tober17, 1947,-".Seria'l"No.P7803156 J'Iihis invention relates .to paper ..making,..and moreparticularly :to stock. :supply means for paper; making machines.

"Qne zoi Ithe .principa1 objects -:of the invention is tojprovideaninlet for; supplyingpapertmaking stock :to .ajF-ourdriniergpapermachine having an open head ,box under controlled conditions ofsubstantially uniform velocity flow rand: distribution :of :fiber;across the width of the machine ,to give a thigh degreerof-uniformity ofweight and .fiberdistribution in the web or 'sheet.

:Another object-is to ;provide .a stock -inlet for azzFourdrinier paper{machine .having anropen head l-box which is adapted ,to discharge stockthrough a slot orifice atlrelatively high and substantially uniformvelocity across itsflateral .extenttoefiect uniform fiber distributionacross the widthcf the machine and which delivers suchstock -,.tothe-headbox at atsufiiciently re- .duced velocity with respect-to thevelocityof. flow through the slot orifice to avoid turbulence and large--.eddy currents while maintaining desired uniformity of flow conditionsacross the machine .from ,the slot orifice .to the. forming wire.

.It isalsoan objectof the invention to provide a .stock supply system.for a Fourdrinier-paper machine having an open head box which includesa pair of oppositely tapered conduits having -a..common discharge.orifice of restricted dimensions to receivestockunderpressure and .todischarge the-stock at .arsubstantiall-y uniform and relativly'jhig'hvelocity across the width of the machine and which alsoincludes as'tockinlet passagearranged to 'deliver the stock ,from the dischargeorifice to the-headbox and diverging I in {the -direction of flow. of"the stock i therethrough -at such an angle as "to (form with Ithe.jdischarge "orifice a TVenturi passage .for dissipating thevelocityenergy. ofthe stock'with minimum turbulenceras thes'tock'flowsfrom the. discharge orifi'ce -to""the head box while "maintaining:subs'tantial ur'iifform'ity of fiber distributionacross"the 'width*dfrthe'machine.

A *further object-is "to provide a ,stock "inlet having; the "above"characteristics which is:readily ada-ptetl f'or atta'chmenttc theexisting open hea'd box-"of a Fourdrini-er'papenmachine "to effectimproved :conditions *of'uniform fiber. distributionthroughoutithe stockin theihea'di box" with- :out 1 producing .undesirable turbulence and.large eddy. currents ,in ,the stock as delivered. to ,the forming .wireand withoutrequiring replacement .onxexpensive rebuildingof .the.existinghead ibox and-slice.

Other-.objectsand advantages. of the invention c cams. (c rca-44) 2.will be :apparent: from ,t'hei following description. "the accompanying:;drawings :and .;the :appended :claims. o

. In ithe :drawings:

.;Fi g. J1 isaamore or'less diagrammatic view in side." elevation,partly broken' away to. show details "of-internal construction,illustrating aiportion Toff a *Fourdrinier paper {machine having {anopen -headhoxandraportion' of the stockisuppl y:system leading :to'thehead .box;

. Fig. 2 :is 1 an "elevational View looking from left to rightin-Fig;lpwith thehead .box and-.a ;part .of the inlet passage removed;

Fig.- ,3.is a sectional view onthe line 3-j,3-.of Fiailrand also .ofFig. 2; and

=Fig..-4ris a diagrammatic viewshowinganother arrangement of stock inletwith a Fourdrinier machine havingan :open head box.

In the drawings, which "illustrate preferred embodiments of theinvention, Figll'shows a portionof :a Fourdrinier paper machine havingan .open headbox'indicated-generallyat l0 forsupplying stock .toaforming wire ll traveling over a breast roll 12. The. stock isinitiallyconveyed tothe. machine from thecollecting box 15 o'ione or -.morescreens indicated fragmentarily .at 1.6. .The .stock from thev.collecting box 15 passes through conduit H .to .a pump I18. driven by.a .motor .19, .and this pump-min ,turn supplies .the stock .to aflmainconduit .20 which 'is'fibranched. at 21 and 22.110 leadtoa pair-ofcounterflowlinle't conduits T24 and .'25,shown as of the ,typeofconstruction disclosed .in LS. Patent "2,34711'1, assigned to the same.alssignee as this application. .AslshownfinFigJB,.theconduits'fl and 25extend generally transversely. of the forming wire H and 'areiseparatedby a bafile 26 except 'forflimi'te'd communication around the ends ofthis baffleja's indicated-M11. The supply of stock'to the conduit-s 124(and 25 may be regulated'by means 'of a variable speed drivefor pump 1.8or .byljaivalve ;such as a ,gatevalve 28 positioned adjacent ;the"discharge side of the pump asshownin "Theba'file '26 is positionedadjacent and par- 'alle'l'to a discharge orifice30 common'to'theitwo'conduits2'4 and 25 and "formed'by a'pairofwalls which will besubstantially higher than the velocity of flow through conduits 24 and25.

It will be noted that the direction of flow through orifice 30 issubstantially at right angles to the direction of fiow of thestock-through'conduits 24 and 25, and in order to minimize possiblenon-uniform velocity, flow conditions because of the flow componentperpendicular to this desired direction of flow through the orifice, the

respective cross-sectional areas of the tapered conduits and the slotorifice are controlled to provide 'a substantial difference .in thevelocity of flow through the orifice as compared with the correspondingvelocity through the conduits 24 and 25. Satisfactory results have beenobtained with these velocities at a ratio of not less than about 4 or5to 1, and with this ratio still higher it is possible to hold thevelocity in conduits 24 and 25' to 'a'low value, for example from 0,5 to2.5 feet per second, such' that the undesired angu- {la'r flow componentis kept to a minimum, while still obtaining desired high velocity ratesof flow through the orifice 30. At such accelerated velocities, fiberfiocs tend to be broken up and the fiber is dispersed in passing throughthe slot orifice, In' addition, since all of the stock is subjected tothe same hydraulic conditions, there is minimum tendencytostratification or separation of light and heavy fibers due to inertiaor centrifugal force. "It will be noted, as shown in Fig, 2, that thetapered conduits 24 and 25 are provided with extension portions 34 and35, respectively, which extend outwardly on opposite sides of themachine and are connected adjacent their outer ends-with the branchconduits 2| and 22. The connections between the conduits 2| and 22 and'the conduit extension portions 34 and 35 are thus located at a sumcientdistance laterally of the machine from the ends of the slot orifice toeffect adequate guiding and straightening of the j "flow. of .stock intoparallel lines of flow before reaching the .slot orifice, satisfactoryresults haviin'gbeen obtained with distances from each end Iofjtheslotto the. center line of the adjacent branch conduit of 2 feet ormore, depending. upon the size of the machine. Furthermore; since thestockis .brought into the conduit exten-- sions 34 and 35 in directionssubstantially perpendicular to their lengths, as shown in Fig. 2,

Ethe velocity of that component of the flow which is perpendicular tothe length of the tapered conduits is largely overcome or practicallyextinguished, and the stock. hasan opportunity to mcr'ease thatcomponent'of flow which 'is in a direction at right angles, tolitsentering direction and to establish substantially parallel lines of flowcrosswise .of the formin wire before reaching the tapered'conduits' andthe slot orifice 30. There is thus provided a cross fiow of stockthrough orifice 30 at a substantially higher velocitjthan the velocityof flow in the tapered conduita in accordance with the supply pressureand theratio of the respective areas of the orifice and the taperedconduits as 'described,.and

4 this velocity and the distribution of fiber and flow in the stock willbe substantially uniform across the Width of the machine.

It is desirable to maintain such uniformity of flow conditions in thestock as it passes from the orifice and is delivered to the formingwire, in order to obtain corresponding uniformity of sheet formationHowever, under most operating conditions with a Fourdrinier machinehaving an open head box, the velocity of fiow through orifice 30 is sohigh that if the stock were allowed to enter the head box at the samevelocity, excessive turbulence and objectionable eddy currentswouldresul-t. If the stock were permitted to enter the head boxvertically at such high velocities, it would tend to spurt above thelevel 'of liquid therein and even above the top of the box itself.Accordingly, the present invention provides means for conveying the highvelocity stock from the orifice 30 to the head box l0 while at the sametime dissipating its velocity energy withminimur'n turbulence anddelivering the stock to the head box' at a substantially lower velocityof flow but with substantially maintained uniformity of both velocityand distribution of fiber across the width ofthe machine for uniformsheet formation. Referring to Fig. 1, an opening 43 is forme in thebottom wall 41 of the head box to receive stock for delivery totheforming wire ll. opening 4|) is substantially wider than the slotorifice 36, as shown in Fig. 1, and extends across the lateral extent ofthe head box adjacent the lower edge of the vertical wall 42. Forexample, satisfactory results have been'obtained in a head box 33 inchesin height with this opening about 6 inches in width as compared with awidth of the order of 4 inch for the slot orifice 3!]. Walls 43 and 44arearranged to form an inlet passage leading from the slot orifice 30 tothe ppening 40 in the bottom of the head box. As shown in Fig. 1, thepassage wall 43 is substantially parallel with the wall 42 of the headbox and extends vertically upwardly from the orifice wall 3|. The wall44, however, is inclined from the vertical and diverges from wall 43 inthe direction of flow of stock frornorifice 30 to opening40. i

The degree of divergence between the passage walls 43 and 44 iscontrolled to a sufficiently small angle to provide a Venturi actionbetween the passage 45 and orifice 30 and thusto provide velocity energyof the stock as it flows upwardly I "in passage 45 while maintaining thesubstantial uniformity of fiber distribution crosswise ofthe passagewhich is imparted to the flow of stock at .the orifice 30. The angularrelation of the passage walls 43 and 44 is of critical importance inobtaining preferred results from the standpoint of this maintenance ofuniform flow conditions, and if this angle is too large, there is atendency for some of the stock to slow down relatively abruptly alongthe outer parts of the passage while the major part shoots through atrelatively high velocity, thus creating a high degree of turbulence andpreventing the desired uniform deceleration of the entire cross-sectionof the flow. Tests indicate that the'total included anglebetween'passage walls 43 and 44 should be not more than about 10 andpreferably somewhat less, for example an angle of the order of 7 Thissuitable slice arrangement, and Fig. lshows the slice as formed by asubstantially rigid lower Wallor lip 50-and a flexible upper plate orlip secured to the front of the head box for vertical adjustment to varythe size of the slice opening. Adjusting means for controlling theposition-of the upper slice lip 5| are indicated generallyat 52 assupported on a suitable plate or bracketfi53 'welded or otherwisesecuredto the front of the head box. Within the head box is a baflie 55"comprising a plurality of vertically spaced portions providing a seriesof apertures or passages 56 through which the stock flows to'theslic'e.Desired results have been obtained in such-cases with the totalcross-sectional area of the: passages 56 substantially equalgto thecorresponding area of the opening 40, thus providing substantially thesame velocity of flow through the passages 56 as the velocity at whichthe stock; enters the head box and causing sufiicient agitation of thestock within the head box to. prevent stagnation and resultingnon-uniform conditions.

:In the operation of'this apparatus-as shown and described,,the pump [8suppliesstock from the collecting box l5 to the conduit 20 and tapered;conduits 24 and i5 at suflicient' pressure to-provide a cross flow ofstock through the orifice 30; at desired high velocity and'volume offlow to 'eifect uniform conditions of velocity and fiber distributionthroughout the entire lateral extent of the, slot 30. As this stock.fiows upwardly through the Venturi passage 45, its velocity energy isgradually and smoothly-absorbed and dissipated as-a result of thedivergence betweenthe passage walls 43 and 44. Thus when thestockreaches the opening 4!] in the bottom of the head box l0, its velocityhas been reduced toa valuesuch that the stock flows into the head boxwithout creating undesirable turbulence or. objectionable eddy currents.In addition, all'the stock is kept in constant motion toward the headbox through the Venturi passage 45 and at a velocity which issubstantially constant across the passage, changes in velocity beingsubstantially uniform crosswise of the passage and taking place smoothlyand with minimum turbulence. The desired conditions of uniform fiberdistribution are thus maintained crosswise of passage 45 throughout itsentire lengthand the stock is delivered through opening 40 under uniformconditions of velocity and fiber distribution across the entire lateralextent of the, head box, thus providing for the desired uniform flowconditions at the slice for effecting uniform sheet formation.

This construction and arrangement of the counterflow inlet and Venturipassage with a Fourdrinier machine having an open head box provide foroperating the machine to produce a sheet of high uniformity at anydesired wire speed within the range afforded by the maximum pressurehead obtainable in a head box of given dimensions. Thus at low speeds,the pressure head within head box ID maybe only 2 or 3 inches, and undersuch conditions the supply of stock from the opening 40' to the slicemay take place entirely through the lowest of the passages 5.6. On theother hand, speeds as high as 1,600 feetperminute have been obtainedwith the pressurehead of the order of 12 feet to give a spoutingvelocity at the slice properly correlated with 55- as well as over thetop of the bafile 55, thus creating sufiicient agitation throughout thehead box to maintain uniform fiber distribution and avoid stagnation ofthe stock. Over all this wide range of operating conditions, thecounterflow inlet and Venturi passage provide desired uniform conditionsof velocity and fiber distribution in the stock across the lateralextent of the head box without undesirable turbulence.

A further advantage of the present invention lies in the fact that thecounterfiow inlet-and Venturi passage arrangement is readily adapted forattachment to the open head box already installed on an existingFourdrinier machine, thus making it possible to achieve the improvedconditions of uniform velocity and fiber distribution without theexpense of replacing the existing head box andslice. For suchinstallations, as well as in new machines, the size of the open-. inginto the head box corresponding to opening 45 in Fig. l is largelydetermined by the, speed at which the machine is to be run and hence thevelocity at which the stock is to be admittedto the head box. Thus for alow speed machine, operating at a wire speed of the order of 200 feetper minute, desired results from the stand point of uniform flowconditions with minimum turbulence have been obtained with this velocityof the order of 1 foot per second, but for higher speed machines adesirable range for this velocity is approximately 1 to 2 feet persecond. The size of the opening 40 is thus properly correlated with thesize of the slot orifice 33 to give the desired velocity range, and thetotal length of the Venturi passage will then be whatever length isrequired to maintain the total included angle between the passage wallswithin the desired range of not more than about 10" as alreadyexplained.

It should also be noted that the stock inlet of the invention makespossiblea substantial reduction in the size of the open head box usedtherewith as compared with conventional open head boxes. Thus accordingto priorpractice, head boxes of considerable length in the directionofwire travel have been used and equipped with a series of baiiles spacedlengthwise of the head box and intended to promote uniform fiberdistribution throughout stock entering the head box from a plurality ofpipes. With the inlet of the present invention, the stock is already insuch highly uniform condition when it enters the head box that suchmultiple bafiles are not necessary and may even tend to decrease ratherthan to improve its uniformity. It is desirable to provide a singlebafile, as shown in Fig. 1, to prevent a direct flow of stock fromopening 40 to the'slice, with resulting stagnation of the stock in theupper part of the box as stated, but more than one such bafile has beenfound undesirable. Furthermore, the size of the two compartments intowhich the bafiie divides the head box need only be sufficient to permitready access for cleaning purposes, satisfactory results having beenobtained with each compartment just large enough to allow a man to enterwith sufficient room for effective cleaning. It will accordingly be seenthat when the stock inlet of the invention is applied to an existingopen head box of the multiple baffle type, the head box should be firstsubstantially reduced in size, to approximately the proportionsillustrated in Fig. 1, thus affording a substantial saving inspace aswell as the improved characteristics of uniform flow conditions asalready discussed. h

It should be understood that it is not necessary to arrange thecounterfiow inlet and Venturi passage vertically as shown in Fig. 1.Thus Fig. e1 shows a modified arrangement in accordance with theinvention in which these parts are arranged for substantially horizontalfiow of stock into the open head box 60 of a Fourdrinier ma:- chineincluding a forming wire Bl traveling over a breast roll 62. The headbox 60 is shown as provided with an internal apertured baflle 85 and anadjustable slice lip arrangement indicated generally at 66, as discussedin connection with Fig. 1. ;;L In the arrangement of Fig. 4, the stockis sup.- plied from a suitable pump and white water return, not shown,to a conduit 10 leading to a screen ll provided with a discharge line 12for reject material. The stock flows from the screen through the supplyconduits indicated generally at 13 to a counterflow inlet constructed asdescribed in connection with Figs. 1 to 3 and including a pair oftapered conduit passages 74 and I5 separated by a baffle 15 and providedwith a com mon discharge orifice l1. Walls 18 and 19 are arranged toform a Venturi passage 80 leading from the slot orifice 11 to theopening 8| in head box 60 to supply stock from orifice TI to the headbox for delivery to the forming wire 61. a

The opening BI is shown as formed in the rear wall 82-of the head box,and it extends laterally across the head box adjacent the edge of thebottom wall 83. The lower wall 18 of the Venturi passage is accordinglyshown as lying in substantially the same horizontal plane as the bottomwall 83 of the head box, and the upper passage wall 19 diverges fromwall '18 in the direction'of flow of stock through the passage, thetotal included angle between the two walls being shown as of the orderof 6 to give the desired Venturi effect. A perforated roll 85 may bepositioned adjacent the slice opening as shown to assure adequatecrossing of the fibers as the stock flows onto the forming wire.

The operation of this system is substantially the same as has alreadybeen described in connection with Fig. 1. The stock supplied to thelarge ends of the tapered conduits l4 and 1,5 is discharged through theslot orifice 11 at apredetermined substantially uniform velocity of flowproducing substantially uniform distribution of fiber across the widthof the machine. The passage 80 cooperates with orifice TI to provide aVenturi action causing the velocity energy of the stock to be dissipatedwith minimum turbulence as the stock fiows from orifice 11 toward thehead box and thus causing the stock to be delivered through opening 8|at a substantially reduced velocity of flow While maintaining thedesired substantial uniformity of fiber distribution across the entirelateral extent of' the head box.

At low wire speeds, the supply of stock to the head box is controlled toa relatively low rate suflicient to maintain the proper'low head withinthe head box, and under such conditions the supply of stock from opening8| to the slice may take place entirely through the lowest of thepassages or apertures 88 through baflie 65. At higher wire speeds,requiring a higher pressure head, the flow through the head box in thedirection of wire travel may also take place through the higher of thesepassages as well as above bafile' 55, thus creating sufiicient agitationthroughout the head box to maintain uniform fiber distribution withoutundesirable turbulence. {Inder all such operating conditions, thecounterflow inlet and Venturi passage coact as described in connectionwith Figs. 1 to 3 to give highly uniform distribution of fiber andfiow'across the head box without undesirable turbulence and large eddycurrents and thus contribute to the desired uniform sheet formation.

Reference is made to my copending applications, assigned to, the sameassignee as this application, Serial No. 607,820 filed July 30, 1945,now Patent Number 2,540,301, and Serial No. 684,980 filed July 19, 1946as a continuationin part of application Serial No. 607,820.

While the forms of apparatus herein described constitute preferredembodiments of the inven-- tion, it is to be understood that theinvention is not limited, to these precise forms of apparatus, and thatchanges may be made therein without departing from the scope of theinvention which is defined in the appended claims.

What is claimed is: i

1. In combinationwith a Fourdrinier pape machine having an open headbox, a stock inlet for supplying paper making stock tosaid head boxunder controlled conditions of uniform velocity'and distribution offiber across the width of said machine without creating turbulence andobjectionable eddy currents in said head box which comprises a pair ofoppositely tapered conduits arranged transversely across said machineand each adapted to be supplied at the larger end thereof with stockunder pressure, means forming a slot orifice common to said pair ofconduits and extending across the full Widtho'i said machine throughwhich said stock isdis' charged from said conduits at'a predeterminedvelocity of flow with substantially uniform distribution of fiber acrossthe width of said ma chine, said orifice being of restrictedcross-sectional area relative to said conduits to maintain saidpredetermined velocity substantially higher than the velocity of flow ofsaid stock in saidco'nduits and substantially uniform across the widthof said machine, walls forming an inlet passage of substantially thesame width as said orifice 'and said head box for conducting said stockfrom said orifice to said head box, said walls diverging in thedirection of flow fromsaid orifice to said head box at a predeterminedsmall angle of not more than 10 to form with said orifice a Venturipassage for maintaining said stool; between said orifice and said headbox in continuous motion towards said head box at a deceleratingvelocity which is substantially constant across each crosssectional areaof said passage to dissipate the velocity energy of said stock withminimum turbulence as said stock flows fromsaid orifice to said head boxwhile maintaining substantial uniformity of flow conditions in saidstock crosswise of said passage and throughout substantially the entirelength thereof, and means forming an open connection of substantiallythe same cross-sectional area as the larger end of said Venturi passagebetween said passage and said head box to admit stock from said passageto said head 'box at a velocity substantially lower than saidpredetermined velocity and with maintained uni formity of flow and fiberdistribution across the width of said machine. I,

2. A stock inlet for delivering paper making stock to a Fourdrinierpaper machine having an open head box which comprises a pair ofoppositely tapered conduits arranged transversely across said machine.and each adapted to be supplied at the larger end thereof with stockacrossthefull width; of said machinethrough.

which; said'stock is: discharged from said con"- duitsat apredetermined. velocity of flow with substantially uniform distribution:of; fiber across thewidthwof said machine, saidorifice being-oirestricted cross-sectional area relative to said. j conduits. tomaintainsaid predetermined velocitysubstantially higher than thevelocity of flow or stock insaid conduits and substantially uniformacross the width-of said machine, walls forming.

an inlet. passage of substantially; the: same width: assaid orificeandsaidhead box for-conducting. stock'from said orifice to saidhead.box, .said walls diverging in the direction of fiow fromsaidori'fice to said head box. at a. predetermined totalincluded angle of notmore than 10 to maintain said stock between said orifice and said headbox in continuous. motion towards said head box at azdeceleratingvelocity which is substantially. constant across each cross-sectionalvarea of said passage, said passage continuing from said orifice to saidhead box with substantially undiminished effective flow area todissipate the velocity energy ofa'said stock with minimum turbulence assaid" stock flows from said orifice to said head box whilemaintainingsubstantial uniformity of flow conditions in said stock crosswise of:said "1 passage and throughoutsubstantially the entirelengththereoflrand. means forming an op'emconi.

nection. between the larger end. of said passage and said head box for.admitting stock from said passage to saidhead box with minimum turbuj vlencevacross the entire width ofsaidlhea'dbox.

3. A stock inlet for delivering paper: making stock to a Fourdrinierpaper machine having an v open head box which comprises means forming anopening in said head box extending across.

the width of said machine to receive stock for delivery to the formingmember of said machine,

walls forming a passage leading to said opening and of substantially thesame width as said head box throughout the entire length thereof, theend of said passage adjacent said head box bein of substantially thesame cross-sectional dimensions as said opening, said walls diverging ata stantially smaller cross-sectional area than said opening extendingacross the width of said ma? chine, and means for supplying stock tosaid ori fice at a substantially uniform pressure across the width ofsaid machine for discharge through said orifice at a predeterminedsubstantially uniform velocity of flow with substantially uniformdistribution of fiber across the width of said ma.-v

chine, the total included angle between said di verging passage wallsbeing not more than 10 to maintain said stock between said orifice andsaid headbox in continuous motion towards said head box at adecelerating velocity which is substantially constant across eachcross-sectional area of said passage while dissipating the velocityenergy of said stock with minimum turbulence as said stock flows fromsaid orifice to said head box and to deliver said stock through saidopening at a substantially lower velocity er...

flow than said predetermined velocity while maintaining substantialuniformity of flow conditions in-said stock across the entire lateralextent of said opening. 1..

4. In combination with a Fourdrinler paper 10 machine having an; open.head. boxvv provided with. an opening in one Wallthereof and extending.across. thetlateral extent otsaid'head: box adja-- cjentanedge of asecond wall thereof to receive. 5' 'stockior. delivery to v the,forming. member. ofv themachine, wallsiormingv a passage leading tovsaid opening. and of substantially the same width as. "said head' box.throughout. the [entire length, "j thereof, the, end of said. passageadjacent. said head. box being of. substantially the samecrosssectionaldimensions. as said opening. and connectingdirectly withisaid headboxthrough said .opening with undiminished effective. flow-area, one ofsaid walls being substantiallyparallel' to 5" said second. wall. of saidhead box, saidwalls -.=-idiverging at.a predetermined-angle inthe.direc-- tion of flow through said passage towardssaidl opening,meansfo-rming aslot. orifice of. substan- -itially smallercross-sectional. area than said. 20 opening extending across the widthofsaidmachine: at the smaller. end of said. passage, and. means for:supplying.,-stock to, said. orifice. at; a. substantiallyuniformpressurev across the, width. of saidmachinerfor discharge throughsaid orificeinto said; passagev at. a. predetermined. substa u tiallyuniform velocity of flowwith substantially uniform; distribution offiber-across. the width of 1 said; machine, the. total included; angle.between 'sfaid diverging passage walls. being. of not. more than :10" toprovide aVenturi .actioninsaidpasP .sag er causing, the. velocityenergyof .said. stock to; be' dissipate'd with minimum .turbulenceassaidstock flows fromsaid orifice; to said; headqbox, said angle betweensaidipassage wallsbeingbelow a predetermined critical angle to maintainsaid .7 stock. between... said rifice. and said opening in continuous-motion towards-said. head box... at; a decelerating velocity which issubstantially constant across each cross-sectional area of said pas-.-.sage and to effect delivery of said stock through said opening at asubstantially lower velocity of 'fiow than said predetermined velocitywhile maintaining substantial uniformity of flow conditions in saidstock across the entire lateral extent of said opening.

A stock inlet for delivering paper making stock to a Fourdrinierpaper'machine having an open head box provided with an opening extendingacross the width of said machine to receive stock for delivery to theforming member of said machine, comprising walls forming a passageadapted for connection with said opening and of substantially the samewidth as said head box throughout the entire length thereof, the end ofsaid passage adjacent said head box being of substantially the samecross-sectionaldimensions as said opening connecting. directly with saidhead box through said opening with undiminished effective fiow area,said walls diverging at a,ppredetermined small angle in the direction offlow through said passage towards said opening, means forming a slotorifice of substantially smaller cross-sectional area than saidopeningextending across the width of said machine at the smaller end of saidpassage, a pair of op- """positely tapered conduits arrangedtransversely across said machine and each adapted to be sup plied at thelarger end thereof with stock under 'i-pressure, and means providing adirect connection from each of said tapered conduits to said nri'fice toeffect discharge of said stock through said orifice into said passage ata predetermined j substantially uniform velocity of flow-withsubstantially uniform distribution of fiberacross the :ividth of saidmachine, the totalincluded angle between said diverging passage wallsbeing not more than 10 to maintain said stock between said orifice andsaidopening in continuous motion towards said head box at a deceleratingvelocity which is substantially constant across each crosssectional areaof said passage and to provide for dissipating the velocity energy ofsaid stock with minimum turbulence as said stock flows from said orificeto said head box and delivery of said stock through said opening at asubstantially lower velocity of flow than said predetermined velocityWhile maintaining substantial uniformity of flow conditions insaid'stock across the entire lateral extent of said opening.

'6. In a stock supply system for a Foul'drinier paper machine includinga formingmember and having an open headbox for supplying stock directlyto said forming member, the combination of a pair of oppositely taperedconduits arranged transversely across said machine and each adapted tobe supplied at the larger end thereof with stock under pressure, meansforming a slot orifice common to said pair of conduits and extendingacross the full width of said machine through which said stockisdischarged through said conduits at a predetermined velocity of flow andwith substantially uniform distribution of fiber across the width ofsaid machine,said orifice being of restricted cross-sectional arearelative to said conduits to maintain said predetermined velocitysubstantially higher than the velocity of flow of said stock in saidconduits and substantially uniform across the width of said machine,walls forming a totally enclosed inlet passage of substantially the samewidth as said orifice and said forming member for conducting stock fromsaid orifice to said headbox, said headbox having an opening therein forconnection withflsaid passage; said passage being of substantially thesame .cross sectional area as said opening at the point energy of saidstock as 'said stock flows from said orifice to said opening whilemaintaining substantial uniformity of flow conditions in said-stockacrossthe Width of said passage over substantially the entire lengththereof. r

STEPHEN A. STAEGE.

REFERENCES CITED The following references are of record in the file ofthis patent:

I UNITED STATES PATENTS 7 Date Number Name 1,775,905 Lang Sept. 16, 19301,964,291 Kutter June 26', 1934 2,243,773 Randell May 27,1941 2,249,128Goldsmith July 15, 1941 2,339,711 Lowe et a1 Jan. 18, 1944 2,347,850Staege May 2, 1944 2,381,286

Hornbostel et a1. Aug. 7, 1945 OTHER REFERENCES Paper TradeJournal,-April 4, 1946, pages 43 and 44,'Sta-ege. I I

